In a 2013 study (Phytother Res 2013: 010.1002 / ptr. 4981), scientists were able to demonstrate significant improvements in body weight and body fat through a natural bioflavonoid mixture of citrus and guarana. After 12 weeks of use, the body weight was reduced on average by about 3 percent and body fat by almost 10 percent. Furthermore, the waist circumference decreased by 6 percent and the hip circumference by almost 5 percent. The subjects did not change their diet nor did they exercise more.